1. Field of the Invention
The present invention relates to a method of providing a pore-sealed surface having a desired finished structure on a lacquered sheet or web material, preferably a lacquered slab or board of a material containing wood fibres (lignocellulose) as well as a slab or board manufactured according to the method.
2. Description of the Prior Art
Wood fibre slabs (for example board, particle board) as manufactured nowadays in their finished state exhibit such drawbacks as great porosity and uneven surface. The production of a satisfactory surface having good surface properties in the final product manufactured from the board is hereby rendered difficult.
At present such surfaces are produced by initially puttying or priming the slabs to even out irregularities of the surface and to obtain a certain pore-sealing in order to reduce the absorption of lacquer paint. Thereafter, the surface is dried, ground and finally lacquer-finished. This surface treatment technique is expensive, wasteful (due to grinding losses) and involves work-hygienic problems due to dusting. When the quality requirements are high as far as the finished surface is concerned, it is necessary to paint the surface in several layers with intermediate grinding.
According to another process known from Swedish Pat. No. 327.126 pore-sealed surfaces on board slabs are manufactured by applying a resin composition to a so-called wet sheet to form a cover of about 10 g/m.sup.2, the sheet subsequently being compressed and dried. Slabs manufactured in this way will have a certain reduced pore-sealing in the surface layer whereas the surface evenness and the appearance of the slab in other respects remain uninfluenced.
According to another known process a drying-oil composition is applied to the surface of a compressed board sheet prior to heat treatment. Thereafter, the oil composition is worked into the surface by powerful mechanical working. This treatment is expensive and requires much time.
The present invention produces a new method of manufacturing a pore-sealed surface having a desired finished structure in a lacquered slab or board of a material containing wood fibres (lignocellulose). The method involves a simplified process elminating the grinding operation and reducing material losses which means lower capital costs and improved working environment. The process also means that the desired surface finish and pore-sealing obtained by a lesser number of steps.
The surface treated slab or board obtained in this way in accordance with the invention may either be used with the given finish or the surface obtained may serve as the supporting underlayer for additional lacquering.
By means of the present invention, a higher degree of pore-sealing and surface finish is obtained as well as the possibility to perform pore-sealing independently of the manufacture of the sheet material as compared with the methods of wet arc coating and oil hardening respectively. These methods in addition require subsequent surface treatment/painting to obtain a surface having satisfactory service properties.
The new process can easily be incorporated into the process as performed in existing plants for the manufacture and/or surface treatment of wood fibre slabs or boards.